#include <stdio.h>

int Sum(int n)
{
    int i = 0;
    int sum = 0;
    for(i = 1; i <= n; i++)
        sum += i;
    return sum;
}
int main()
{
    printf("hello world\n");

    int ret = Sum(100);

    printf("%d\n",ret);
    return 0;
}
